Solitary benign schwannoma in the psoas muscle

Schwannomas, which also are referred to as neurinoma or neurilemmoma, are rare. We report a case of a solitary benign schwannoma in the psoas muscle, which was not associated with von Recklinghausen's disease. The tumor was excised successfully. Its appearance on clinical examination is described, the preoperative investigations and operative findings are presented, and the literature is reviewed.     

Solitary benign schwannoma of the brachial plexus

A solitary benign Schwannoma of the brachial plexus unassociated with von Recklinghausen's disease is presented. The initial presentation is usually that of a painless, supraclavicular mass, but this patient had a tingling sensation in the right forearm. Local excision was performed. The literature is reviewed.     

A case of schwannoma in psoas muscle

We report a case of schwannoma in psoas muscle, difficult to make a preoperative differential diagnosis from multilocular renal cyst in a 44-year-old woman. She complained of epigastric discomfort, and abdominal computerized tomography revealed a left multi-cystic renal tumor. Drip infusion pyelography showed the tumor displacing the left kidney superiorly, and pushing the left ureter medially. Magnetic resonance imaging demonstrated that the tumor structure was multilocular. At the operation, the tumor was observed in psoas muscle and was revealed as schwannoma in microscopic findings.     

Laparoscopic resection of ancient schwannoma embedded in the psoas muscle

Schwannoma is a tumor originating from the Schwann cell of the peripheral nerve sheath. The diagnosis of schwannoma is based on histologic analysis of surgically excised sample. Retroperitoneal ancient schwannoma, a variant of schwannoma, is rarely observed in clinical practice. We report the case of a 46-year-old man with a retroperitoneal tumor embedded in the psoas muscle, which was treated by laparoscopic resection. The operative result was good, and pathologic analysis revealed a 5.5 × 4.5 cm ancient schwannoma.     

Solitary psoas muscle metastasis after radical nephrectomy for renal cell carcinoma

Skeletal muscle is a very rare location for the metastasis of renal cell carcinoma (RCC) and only one case of solitary metastasis to the psoas muscle has been reported. We present a 63-year-old male patient with late recurrence (14 years) after left side radical nephrectomy for RCC. He first visited Chikushi Hospital, Fukuoka University, Japan in January 2000 for a postoperative follow-up because he had shifted residence to the area. Follow-up was by abdominal computed tomography (CT) and chest X-ray. In December 2001, a CT scan showed a 1.5 cm enhanced mass in the right psoas muscle without any other metastasis. The mass was resected that month and histological study showed RCC metastasis.     

Solitary schwannoma of the glans penis

Schwannomas of the penis are extremely rare. A 69-year-old man presented with a circumscribed asymptomatic tumor on the dorsum of the glans penis. Histopathologic examination of the surgical specimen showed a benign schwannoma.     

Solitary ectopic intracerebral schwannoma.

Intracerebral Schwannoma is a rare tumour which can mimic meningioma clinically, radiologically and morphologically. Immunohistochemical techniques are necessary to confirm the Schwann cell origin of the tumours. We report such a tumour in the posterior frontal parasagittal region. The origin of Schwann cells in the central nervous system is still speculative and various postulations are discussed.     

Solitary intracerebral schwannoma in von Recklinghausen's disease

A case of intracerebral schwannoma of the frontal region in a patient with mixed neurofibromatosis is reported. The possible origins of the tumor are discussed.     

Primary benign mesenteric schwannoma

Schwannomas, also known as neurilemmomas, are benign tumours arising from the sheath of peripheral nerves in the soft tissues of head, neck, extremities, mediastinum and retroperitoneum. Schwannomas are relatively slow-growing and mostly benign. Primary mesenteric schwannoma is extremely rare. In this report, we describe a 45-year-old female who presented with a lump in the abdomen caused by a benign schwannoma originating from the mesentery of the small bowel, which was treated with surgical resection and marsupialization of the remnant capsule on the posterior side. A high grade of suspicion is required to diagnose such a tumour. Ultrasonography is generally inconclusive, but histopathological examination can confirm diagnosis. The patient was followed up for six months without evidence of disease recurrence.     

Primary hepatic benign schwannoma

Schwannoma is predominantly a benign neoplasm of the Schwann cells in the neural sheath of the peripheral nerves.Occurrence of schwannoma in parenchymatous organs,such as liver,is extremely rare.A 64-year-old man without neurofibromatosis was observed to have a space-occupying lesion of 23mm diameter in the liver during follow-up examination for a previously resected gastrointestinal stromal tumor(GIST)in the small intestine.He underwent lateral segmentectomy of the liver under a provisional diagnosis of hepatic metastatic recurrence of the GIST.Histological examination confirmed the diagnosis of a benign schwannoma,confirmed by characteristic pathological findings and positive immunoreactions with the neurogenic marker S-100 protein,but negative for c-kit,or CD34.The tumor was the smallest among the reported cases.When the primary hepatic schwannoma is small in size,preopera- tive clinical diagnosis is difficult.Therefore,this disease should be listed as differential diagnosis for liver tumor with clinically benign characteristics.     

Solitary recurrent malignant schwannoma of the chest wall

A case of solitary recurrent malignant schwannoma of the chest wall seen in a young adult is presented. The clinical and pathological features of this rare neoplasm are discussed.     

Chronic expanding hematoma in the psoas muscle

We report an unusual case of chronic expanding hematoma in the psoas muscle. A 53-year-old man was admitted for evaluation of a mass shadow in the left lower lung field on chest X-rays. He had also been suffering from dull left back pain. A computed tomography scan showed a cystic lesion with a rim enhancement in the left retroperitoneal space. Mixed signal intensity in a mosaic pattern was seen on a T2-weighted magnetic resonance image. We could not rule out a suspicion of a neoplastic intratumoral hemorrhage. Due to increased pain and the definite diagnosis, surgery was performed. Histopathological examination confirmed the diagnosis of chronic expanding hematoma. The expansion process is thought to be due to the irritant effects of blood and its breakdown products, which cause repeated exudation and bleeding from capillaries in the granulation tissues.     

Gigantic benign schwannoma in the lateral peroneal nerve

While schwannomas of the lateral peroneal nerve at the neck of the fibula are rare, this entity should be considered in the differential diagnosis of popliteal cysts and in all cases of pain or paresthesia of the leg and foot. Magnetic resonance imaging is the diagnostic tool of choice for diagnosis of schwannoma.     

Solitary dorsal intramedullary schwannoma. Case report

A case of solitary dorsal intramedullary schwannoma diagnosed by magnetic resonance imaging and treated surgically is reported. The authors review the previously published cases. The possible etiology of the tumor as well as some difficulties encountered in the diagnostic procedure and treatment are discussed.     

Primary pyogenic abscess of the psoas muscle

Summary. During a six-year period, eleven persons with primary pyogenic abscess of the psoas muscle were treated at the Mackay Memorial Hospital. Five were males and six were females and their average age was 47.2 years (range 6 – 83 years). The abscess was identified by CT in 7 patients, MRI in 2 and ultrasonography in 1. One abscess was found during laparotomy. Treatment included extraperitoneal drainage of the abscess in 7 patients and CT guided aspiration in 3. One patient improved after antibiotic therapy and they all recovered after treatment. The diagnosis of primary pyogenic abscess requires a high index of suspicion and the best treatment is early operative drainage and administration of systemic antibiotics.

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Résumé. Sur une période de 6 ans nous avons traité 11 abcès pyogéniques primaires du psoas au Mackay Memorial Hospital. Ces cas comprenaient cinq hommes et trois femmes. Leur age moyen étaient de 47.2 ans (compris entre 6 et 83 ans). Sept cas ont été identifiéà l’aide d’un scanner, deux l’ont été par résonance magnétique et un par échographie. Un dernier cas a été observéà l’occasion d’une laparotomie. Le taitement comprenait dans sept cas un drainage extrapéritonéal ainsi que trois succions guidées sous scanner. Un cas s’est amélioréà la suite d’un traitement antibiotique. Tous les patients ont recupéréà la suite de ce traitement. Le diagnostic d’un abcès pyogénique primaire nécéssite un indice de probabilitéélevé et son meilleur traitement consiste à effectuer un drainage chirurgical et à prescrire des antibiotiques systémiques.

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Accepted: 25 November 1996